Okay, if you use Chrome (or Firefox), chances are someone has recommended the "Stylish" plugin/extension to you at some point. Maybe you use (or used) it. It turned into a Chinese ad farm at some point, so an open source version of the plugin, "Stylus," replaced it as the browser-styling extension du jour.

I've been using Stylus for years now. Mostly to put a dark theme on every site on the internet, but... well yeah, actually just for that. So weird that huge sites like Facebook, Instagram, Reddit, Wikipedia, Amazon, etc. all refuse to implement a simple native "night mode," but other users are perfectly happy to code one up for you.

Anyway, the catalog of styles everyone uses for these plugins is Userstyles.org, but it's unmaintained and had been grinding to a halt over time, and now appears to have entirely stopped. Witness: https://userstyles.org/

Wasn't that fun?

Yeah, it's totally dead. But here's a github-hosted copy somebody archived. I dunno if it's everything, but I just used it to install a style to my browser, so looks like it works: